A French company claims to have grown human sperm cells in a laboratory for the first time.

The Kallistem Laboratory, in Lyon, said it had produced sperm cells using patient testicular biopsies that contained immature germ cells, but the research is yet to be published in a peer reviewed journal.

The researchers claim that their work will enable them to extract reproductive cells from a male patient and store them until he decides to have a child. So far this process has proved effective in mice but still needs to be tested in humans.

The company said it will be holding pre-clinical trials in 2016 and, if they're successful, clinical trials may go ahead in 2017.

Isabelle Cuoc, Kallistem's CEO, said: 'Our team is the first in the world to have developed the technology required to obtain fully formed spermatozoa in vitro with sufficient yield for IVF. This is a major scientific outcome that enhances both our credibility and our development potential.

'We are targeting a global market worth several billion euros in which there are currently no players.'

Nonetheless, some scientists are treating this research with caution until it is proven. Allan Pacey, professor of andrology at the University of Sheffield, told the Daily Mail: 'This is a bold claim to make and we have had our fingers burnt before. Until I see a peer-reviewed scientific publication showing unequivocally that this has been done, I have to remain sceptical.'

He added: 'Claims like this can often cause heartache for infertile couples who see them as hope, only to have their hopes dashed later when it doesn't translate into an available procedure.'

Nathalie Rives, manager of the CHU fertility clinic in Rouen, France, told Le Figaro: 'If it works, this procedure opens great prospects.' Though, she added that some men might have 'genetic anomalies' which could exclude them from the process.